1. Field of the Invention
This invention relates to melt-processable, radiation cross-linkable ethylene/chlorotrifluoroethylene copolymer compositions.
2. Description of the Prior Art
It has been proposed to irradiate ethylene/chlorotrifluoroethylene copolymers to improve their tensile strength at high temperatures as well as other properties. The proposed ionizing radiation includes X-rays, gamma rays, electron beams, etc. It has also been proposed to heat the copolymers subsequent to irradiation to improve mechanical properties and to incorporate a small amount of a cross-linking promoter such as triallylcyanurate into the copolymer prior to irradiation to reduce the radiation dosage.
It has been found that ethylene/chlorotrifluoroethylene copolymer compositions including triallylcyanurate or its position isomer, triallylisocyanurate, are not melt processable, such as by extrusion or injection molding, due to the high temperatures required for such melt processing operations and the extrudates have a discolored and bubbled appearance. Melt processing temperatures above about 250.degree.C. are required to fabricate articles such as valves, gaskets, papers, wire insulation, sheets and films and at such temperatures, the copolymer compositions rapidly increase in viscosity and eventually "set up" when extruded or molded. It has further been found that such compositions emit an odor when irradiated and develop bubbles after irradiation.